Seems like another case where common sense as opposed to intricate engineering introspection is the order of the day. How gratifying for the student that they were able to wade in and make a difference in such short order. Definitely a tactic for keeping that student engaged with further study around satellite communications systems.
You're right, Jenn. Usually the common sense solution doesn't come in until technology solutions have been exhausted. On this one however, I would think the simple solution would have been tried first, not last. Maybe that's just because I grew up having to move the antenna -- whether on the roof or on the TV -- in order to make things work -- like a decent TV picture.
Seems like a lot of training for such a simple solution. Sometimes the simplest solution is right in front of you. And I agree, it is great that the student was able to go and take care of the noisy channel.
Note the author said he'd erred years before with antenna pointing. He had first-hand experience with the problem, and passed it on to his student as one thing to try. I would hesitate to call this particular Sherlock Ohms straight forward, or requiring common sense.
Good point Naperlou. This case of Sherlock Ohms really does require both experience and logic. Most of these entries require some combination of the two. I would imagine the experience comes through as a form of intuition, while the logic is a cool-headed effort to look at a system without assumptions.
Looks like it falls under understanding *all* the hardware, specificly high gain antenna gain plots.
Once you know highly directional high gain antenna designs have multiple relatively high gain lobes off the axis of the main (highest) gain lobe, then the possibility of a secondary lobe being aimed at the signal source leaving the highest gain main lobe pointed somewhere else leading to excessive S/N ratio becomes an obvious possibility.
Definitely a good real world example following an introduction to antenna gain plots in future teaching situations.
This solution makes me wonder whether the antenna will have to be adjusted over the course of time. Certainly that was true of TV antennas. Is this case, a constant signal may mean there will not be variation over time. Is that correct?
Shouldn't need adjustment as long as the antenna (and the structure/tower/building) remain in the same place and the satellite remains at the same geosyncronous point in orbit (or for the TV reception case the transmitter tower isn't moved). A moderate to severe earthquake may ruin your day aim wise if your near the fault, perhaps also hurricanes/tropical storms, etc. if a mast gets bent a little or a clamp slips), but continental drift shouldn't be a problem in your lifetime.
Not sure how well the stationaly geosyncronous birds do long term for orbital accuracy however -- there's another hardware system question to ask & understand. The higher the gain and narrower the beam angle, the more sensitive you'd be.
This story verifies that ancient piece of wisdom that "a chain is only as strong as it's weakest link". This certainly is applicable to systems that use antennas of any kind. OF course, knowing that already a bunch of well trained people had checked the rest of the system may have helped with recognizing the clues a bit.
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